Machine for graining lithographic plates



March 1933.. c. A. BECKETT MACHINE FOR GRAINING LITHOGRAPHIC PLATES Filed April 16, 1931 2 Sheets-Sheet 1 Jrwowlim CHHRLES ILBECKETT,

. March 7, 1933. c A, BECKETT 1,900,090

MACHINE FOR GRAINING LITHOGRAPHIC PLATES Filed April 16, 1931 2 SheetsSheet 2 57 1 N J u 4 58 I i E W i d Jwucwvww/ CHARLES ILBECKETT,

fl L 119 M Patented Mar. 7, 1933 PATENT.

CHARLES ARTHUR BECKETT, 0F HULL, ENGLAND MACHINE FOR GRAINING- LITHOGRAPHIG PLATES Application filed April 16, 1931, Serial No. 530,527, and in Great Britain April 25, 1930.

set up a grinding action on the plates due to the gritty substance and gradually pro duce the required grain in the surface of the plates. a

The object of this invention is to provide an improved construction of machine in which the plates are normally supported in a horizontal position whilst being grained and the graining elements caused to leave the plates, whilst operatively acting thereon, at a speed which canbe determined to suit the requirements of the operator and in'which the graining elements can be collected in a container adapted for manipulation so as to return them in bulk into the trough.

According to this invention a machine for graining lithographic plates comprises a trough mounted on a'framing and adapted to belsubjected to a circular shaking movement, a tiltable false bottom to the trough to which the plates are adapted to'be secured at least one tiltable container for graining elements carried in the trough, .said tiltable false bottom and container being tiltable independently of and towards one another for the transference of graining elements from one to theother, means for retaining graining elements operatively in the trough, means for'operating the trough and means for mechanically tilting the false bottom independently of the tiltable container and of the trough so as to effect discharge ofigraining elements therefrom into said tiltable The tiltable false bottom is raised during the operation of the machine for discharging the graining elements into the tiltable container and the means for so raising it may be an arrangement of levers operable byhand lever. v

The movable collecting container or containers is or are arranged in a Well to permit washing of the graining elements therein and may be hinged to the trough or an extension thereto so as to admit of being tilted to- Wards the trough by hand or mechanically for returning the graining elements into the trough.

Referring to the drawings filed herewith Fig. 1 is a side elevation of one form of machine made in accordance with-this invention;

. Fig. 2 is a plan;

Fig. 3 is a rear elevation;

Fig. 1 being a plan of same with the trough removed.

2 is a standard or framing having at each of its four corners a cup 3 with a loose ball a therein. Resting on the balls a is a rectangular trough 5 having a false bottom 6 hinged at three points 7 to across bar 8. The trough 5 has an integral extension 9 having a well 10 in which is housed a perforated container 11 for holding the graining elements such as marbles or thelike, said container being hinged at 12 to the cross bar 8 and supported by brackets 13 secured to the side of the trough whereby it can be raised or tilted about its hinge towards the trough as shown in dotted lines in Fig. 1. The false bottom 6 being also hinged to the crossbar 8 can be raised as indicated in dotted lines in Fig. 1. Brackets 1 1 secured to the sides of the trough carry a cross bar 15 supporting a drop apron 1G hinged thereto which in its lowered position rests adjacent to the hinged side of the false bottom 6 and forms a closure member thereat to the trough. The brackets 141 are provided with arms 17 inclined inwardly to form supports for the apron 16 when raised- The apron is adapted to be a driving shaft 20 for operating the trough 5, this shaft being provided with a loose pulley 21, and a driving pulley 22 operated by belt in a well known manner, the usual belt shifting apparatus 23 being provided. The base of the trough 5 is provided on its underside and at two opposite ends with housings 24 for the upper ends of crankshafts 25 which are mounted in housings 26 secured to the framing 2. These crankshafts are provided at their lower ends with bevel wheels 2'? meshing with and driven by bevel wheels 28 on the driving shaft 20 whereby the trough is operated and subjected to a circular movement determined by the throw of the cranl-Zshafts 25 which may for example be one inch or any other suitable amount found. to be convenient.

The container 11 is provided with a handle.

26 for the attachment of a wire rope 27 for raising said container, the wire rope passing over pulleys 28 from a drum 29 operated by a hand lever 30 through worm and worm wheel (not shown) in well known manner and carried in the housing 31 which may be a separate unit from the machine or incorporated with or attached to the structure framing 2.

For raising the false bottom 6 a bracket 32 is attached to the free end thereof and connected to this bracket is a lift rod 33 operable by a hand lever 3d through the medium of a lever 35 and balance Weight 36 keyed to a spindle 3'? mounted in brackets 38 and 39 attached to the framing 2. The connection of the lift rod 33 to the lever 35 and bracket 32 is such as to allow for the play re quired owing'to the circular shaking movement of the trough 5. The hand lever 34 is held by a trigger 4O operable therewith over a quadrant 41 secured to the framing.

In use, lithographic plates are secured in any suitable manner to the false bottom 6 of the trough 5 and marbles (not shown) discharged on to the plates by tilting the containers 11, water and a sprinkling of the required gritty substance being added, the ma chine is then set in motion by manipulating the belt shifting apparatus so as to permit the driving shaft 31 to rotate and the bevel. wheels 28 thereon rotate the engaging bevel wheels 27 which in turn operate the crankshafts 25 for actuating the trough 5. After the requisite time has elapsed for the plates to have become grained by the action of the marbles or the like and whilst the machine is still operating, the drop apron 15 is released and raised clear of the false bottom 6 as indicated in dotted lines in Fig. l, and the hand lever3 l is manipulated. to raise the false bottom also as indicated in dotted lines in Fig. 1, whereupon the marbles or the like gradually fall into the containers l1, themachine is then stopped an d the removed and substituted by new ones for another operation.

With a machine made according to this invention the trough can be operated at a greater speed and plates grained in less time than it usually takes at present, resulting in a sharper, deeper and cleaner quality of grain than hitherto.

Further, owing to the marble collecting container being hinged and normally at rest in the Well, the marbles are quickly cleaned as they fall into the container owing to the surrounding water in the well.

It is found that a machine made according to this invention can be run at a greater speed than machines as hitherto constructed and in consequence of such speed the result ant motion of the marbles is that of a spinning motion as against a rolling motion hitherto, which results in a much more uni form and satisfactory graining being obtained.

What I claim and desire to secure by Letters Patent, is

1. A machine for graining lithographic plates comprising a trough mounted on a framing and adapted to be subjected to a circular shaking movement, a tiltable false bottom to the trough to which the plates are adapted to be secured, at least one tiltable container for graining elements carried in the trough, said tiltable false bottom and corn tainer being tiltable independently of and towards one another for the transference of graining elements from one to the other,v

means for retaining graining elements operatively in the trough, means for operating the trough and means for mechanically tilting the false bottom independently of the tiltable container and of the trough so as to effect discharge of graining elements therefrom into such tiltable container. 7

2. A machine for graining lithographic plates comprising a trough mounted on a framing and adapted to be subjected'to a circular shaking movement, a tiltable false bottom to the trough to which the plates are adapted to be secured, said false bottom'being hinged about an axis located in the trough, at least one container for graining elements hinged about said axis of said false bottom and tiltable towards the false bottom independently thereof, means adaptable for forming V a removable closure to the trough in proximity to the axis of the false bottom, means for operating the trough and means for mechanically tilting the false bottom.

plates comprising a trough mounted on a framing and adapted to be subjected to a circular shaking movement, a graining compartment and a well to the trough, a tiltable false bottom in the graining compartment of said trough to which the plates are adapted to be secured, at least one container for graining elements in said well tiltable towards 3. A machine for graining lithographic said false bottom independently thereof, means adaptable for forming a. removable closure to the graining compartment, means for operating the trough and means for mechanically tilting the false bottom.

4. A machine for graining lithographic plates comprising a trough, mounted on a framing and adapted to be subjected to a circular shaking movement, a tiltable' falsebottom to the trough to which the plates are adapted to be secured, at least one tiltable container for graining elements carried in the trough, said tiltable false bottom and container beingtilt'able independently of and towards one another for the transference of graining elements from one to the other,

means for retaining graining elements operatively in the trough, means for operating the trough, means for mechanically tilting the false bottom so as to effect discharge of a graining elements therefrom into the'tiltable container, and means for mechanically tilting said contalner.

In testimony whereof, I affix my signature.

CHARLES ARTHUR BECKETT. 

